Combination alkali metal pyrophosphate-alkaline earth metal pyrophosphate detergent builder

ABSTRACT

Alkali metal pyrophosphates and alkaline earth metal pyrophosphates are combined to provide a builder system for detergent compositions.

BACKGROUND OF THE INVENTION

The present invention relates to the use of alkali metal pyrophosphatesand alkaline earth metal pyrophosphates which are particularly adaptedto reducing water hardness. The alkali metal pyrophosphate and alkalineearth metal pyrophosphate may be used alone as an additive product orformulated into a complete detergent composition. Additive products areintended to supplement the consumer's regular detergent product as apresoak or by direct addition to the wash solution with the consumer'sdetergent. The detergent composition of the present invention includesan organic detergent as an additional component to the alkali metalpyrophosphate and an alkaline earth metal pyrophosphate.

Builders are important to detergent compositions in that a builderfunctions to control water hardness. If an ineffective builder orineffective amounts of a builder are used cleaning performance by thedetergent is lessened. The lack of builder capacity is evidenced bymeasuring the reflectivity of fabrics washed in hard water versuscontrol fabrics washed in the absence of hard water where reflectance isgreater.

Detergent builders have for the most part been classified assequestering or precipitating. Sequestering builders include forexample, such materials as water-soluble tripolyphosphate, citrate,ethylene diamine tetraacetate, and organic phosphonates. Alkali metalpyrophosphates are also classed as sequestering builders.

Precipitating builders are materials such as the alkali metalcarbonates, bicarbonates, sesquicarbonates, silicates, aluminates,oxylates, and fatty acids, particularly the sodium and potassium salts.

The distinction between precipitating and sequestering builders, isstated to be whether or not a significant amount of precipitate isformed when the builder is used in an amount sufficient to combine withall of the calcium ions in solution. A builder such as sodiumtripolyphosphate when used at a level of about 0.06% by weight in asolution containing 7 grains of calcium hardness is not classed as aprecipitating builder as no precipitation occurs. As thetripolyphosphate has controlled the hardness, the mechanism issequestration. Sodium carbonate, however, is classed as a precipitatingbuilder when used at the same concentrations as the sodiumtripolyphosphate in a 7 grain solution of calcium ions as the carbonatewill eventually precipitate as calcium carbonate, even though the rateof precipitation is slow.

Precipitating builders such as sodium carbonate which exhibit extremelyslow rates of precipitation with calcium ions are frequentlyinsufficient to prevent intereference by the calcium ion with thedetergent thereby impairing the cleaning of the fabrics. Thisintereference takes place primarily at the site of body soil stainswhere the calcium ions become affixed to the carboxyl radicals in thefatty acids of the body soil. Another way in which the calcium ionsinterfere with the detergency process is that they combine with thedetergent component to lessen the detergents effective concentration.For instance, alkyl benzene sulfonates are anionic detergents which maybe precipitated by calcium ions to the extent that on a stoichiometricbasis one mole of calcium ion solution will precipitate 2 moles of alkylbenzene sulfonate, thus substantially lowering the amount of detergentactive available for cleaning.

As was previously mentioned the sodium carbonate would if givensufficient amount of time precipitate most of the calcium ions. Duringthe course of a wash cycle which is generally from 10 to 12 minutes, thecalcium ions do not precipitate but predominantly associate as a solublespecies in a 1:1 ion pair with the carbonate anion. This soluble calciumcomplex has a binding constant much less than that found in the calciumtripolyphosphate sequestered complex. To improve the effectiveness ofsodium carbonate as a detergent builder it has been suggested in BelgiumPat. No. 798,856 issued Oct. 29, 1973, herein incorporated by reference,that a crystallization seed such as calcium carbonate be included in thecomposition. The use of the crystallization seed provides a two-foldbenefit. First, the calcium ions in the wash solution are rapidlydepleted by the precipitation of the calcium and carbonate ions onto thesurface of the crystallization seed, and second, that once precipitatedupon the crystallization seed the calcium ions are no longer free tointerfere with the organic detergent components.

It was previously stated that the alkali metal pyrophosphates with whichthe present invention is concerned, are classed as sequesteringbuilders. Sodium pyrophosphate is the equivalent of sodiumtripolyphosphate in that both possess the ability to sequester one moleof calcium hardness per mole of the respective polyphosphate anion. Thissequestration by pyrophosphate is extremely rapid and permanent in thatthe calcium ions once sequestered do not to any appreciable extentbecome free again. Indeed sodium pyrophosphate in a composition oflimited phosphorus content is more advantageous to use thantripolyphosphate because the molecular weight of the pyrophosphate islower than that of the tripolyphosphate thus allowing more moles ofpyrophosphate anion to be present than of the tripolyphosphate anion ata given phosphorus content.

It has now been found that alkali metal pyrophosphates are made muchmore effective in their building capacity when used in conjunction withfinely divided particles of calcium pyrophosphate. It was previouslystated that the alkali metal pyrophosphates were previously known fortheir use in detergent product as sequestrants of water hardness. Whilenot wishing to be bound by any particular theory it appears that thecalcium pyrophosphate causes the alkali metal pyrophosphates toprecipitate rather than only sequester calcium ions in the wash. Some ofthe effect of the calcium pyrophosphate alone may be to assist inincreasing the reflectivity of the washed fabric.

Whereas sodium pyrophosphate sequesters calcium ions on a 1:1 molarbasis, it will precipitate as the dicalcium salt on the finely dividedcalcium pyrophosphate in a ratio of 2 moles of calcium ion per mole ofsoluble pyrophosphate. Thus substantially larger amounts of calcium ioncan be controlled by precipitation than by sequestration.

It is thus an object of the present invention to prepare a detergentadditive or complete detergent composition containing an alkali metalpyrophosphate as a detergent builder.

It is yet a further object of the present invention to prepare adetergent composition or detergent additive containing calciumpyrophosphate.

Yet a further object of the present invention is to prepare a detergentadditive or complete detergent product containing as a builder system analkali metal pyrophosphate which is of an increased effectiveness indepleting water hardness and maintaining whiteness through the use ofcalcium pyrophosphate.

Percentages and ratios throughout the specification and claims are byweight unless otherwise indicated. Temperatures are by degreesFahrenheit unless noted otherwise.

SUMMARY OF THE INVENTION

The present invention has two aspects. The first is a detergent additivecomprising:

a. an alkali metal pyrophosphate; and

b. an alkaline earth metal pyrophosphate having a mean particle diameterof less than 25 microns; in a weight ratio of the alkali metalpyrophosphate to the alkaline earth metal pyrophosphate of from about60:1 to about 1:8.

A second aspect of the present invention is a detergent compositioncomprising:

a. from about 5% to about 60% by weight of an alkali metalpyrophosphate;

b. from about 1% to about 50% by weight of an alkaline earth metalpyrophosphate having a mean particle diameter of less than 25 microns;and

c. from about 2% to about 40% by weight of an organic detergentcomponent.

DETAILED DESCRIPTION OF THE INVENTION

The alkali metal pyrophosphates of the present invention arecommercially available from several sources. Preferably the alkali metalpyrophosphates of the present invention are the sodium and potassiumsalts, especially sodium. The choice of the physical form of the alkalimetal pyrophosphate to be employed herein is not particularly important,however, some advantages may be noted for one form over another. Thusthe anhydrous salts or hydrates of the alkali metal pyrophosphates areemployed herein. When the composition is in granular form it ispreferred that the granules be of the size of granules in commerciallyavailable detergents to ensure rapid dissolution and for consumeraesthetics. While the anhydrous pyrophosphates may be used in thepresent invention there is no particular advantage because in severalmodes of the present invention the pyrophosphate will be contacted withan aqueous slurry.

The alkaline earth metal pyrophosphates of the invention such as thecalcium or magnesium salts thereof, particularly calcium, are employedin the present invention as a crystallization seed upon which waterhardness ions associated with the alkali metal pyrophosphatesprecipitate. It is believed that to provide for the most effective useof the crystallization seed, that the calcium pyrophosphate particlesshould have a large surface area available for crystal growth and thatthe crystallization seeds themselves be present in a sufficiently largenumber to ensure that they are dispersed throughout the solutioncontaining the water hardness.

The rate at which the hardness may be depleted by precipitation at agiven alkali metal pyrophosphate content is a function of the number ofparticles of the alkaline earth metal pyrophosphate present in thesolution containing hardness. With greater numbers of crystallizationseeds present in the solution, there is a greater probability that thewater hardness to be precipitated will come in contact with thecrystallization seed. The surface area of the alkaline earth metalpyrophosphate available for crystallization growth is also a function ofthe number of particles present per given weight of the alkaline earthmetal pyrophosphate. Thus for a given crystal structure of the alkalineearth metal pyrophosphate the mean particle diameter defined as thelongest axis of the particle, will be determinative of the nominalsurface area. Otherwise stated the known geometry of the particle andmean diameter thereof allow the calculation of the nominal surface area.

In discussing the surface area, it is assumed that the crystallizationseed has not been deactivated or poisoned by a material which wouldinhibit the growth on the crystal surface of the reaction product of thewater hardness salt and the pyrophosphate anion.

Herein particle size is used as a convenient measure of the surface areaof the alkaline earth metal pyrophosphate.

To be effective as a crystallization seed the alkaline earth metalpyrophosphate has a mean particle diameter of less than 25 microns,preferably from about 0.01 to about 1.0 micron, and most preferably fromabout 0.01 to about 0.20 micron. The surface area of the alkaline earthmetal pyrophosphate crystallization seed should be greater than 1 squaremeter per gram, preferably greater than 20 square meters per gram, andmost preferably greater than 100 square meters per gram.

Alkaline earth metal pyrophosphates useful in the present invention maybe prepared in accordance with the methods described in U.S. Pat. No.2,876,166 to Nebergall on Mar. 3, 1959, and U.S. Pat. No. 2,876,168 toBroge et al, patented Mar. 3, 1959.

Briefly summarized the alkaline earth metal pyrophosphates, and inparticular calcium pyrophosphate, may be prepared by heating dicalciumorthophosphate dihydrate to a temperature from about 100°C to about300°C to drive off the water of hydration thus forming anhydrousdicalcium orthophosphate. The anhydrous dicalcium orthophosphate is thenheated to a temperature above about 300°C to drive off the water ofconstitution resulting in the formation of calcium pyrophosphate (Ca₂ P₂O₇). The alkaline earth metal pyrophosphates if not of the requisitesize and surface area may be made finer by colloid mills which are usedto grind the alkaline earth metal pyrophosphate to the desired particlesize.

In the detergent additive aspect of the present invention the weightratio of the alkali metal pyrophosphate to the alkaline earth metalpyrophosphate is from about 60:1 to about 1:8, preferably from about20:1 to about 1:1, and most preferably from about 10:1 to about 2:1.While the amount of alkali metal pyrophosphate used to precipitatehardness is theoretically set at one-half the amount necessary forsequestration, slightly larger amounts are desirable so that somesoluble pyrophosphate is available in the wash to peptize and suspendsoil.

To either the additive composition or the complete detergent product ofthe present invention supplemental alkaline materials may be included toprovide a reserve source of alkalinity to keep the pH of the solutionfrom which the hardness is to be depleted above 8, preferably above 9.The purpose of the supplemental alkaline materials is to provide a pHwhere the precipitation product of the water hardness and the alkalimetal pyrophosphate is most favorable. Preferably the supplementalalkaline material is an alkali metal carbonate or an alkali metal oralkaline earth metal hydroxide and mixtures thereof. Alkali metalsilicates of the formula SiO₂ :M₂ O may also be employed to provide thebenefit of the supplemental alkaline material. The alkali metalsilicates generally have an SiO₂ :M₂ O weight ratio of from about 1:1 toabout 4:1. Preferably the alkali metal silicate is the sodium orpotassium, especially the sodium salt thereof. Examples of the alkalimetal carbonates are sodium and potassium carbonate, while the alkalimetal hydroxides are preferably sodium or potassium and the alkalineearth metal hydroxide is preferably calcium hydroxide. These alkalinematerials are employed at a level of from about 1% to about 30%,preferably about 3% to about 20% by weight.

When the product of the present invention is formulated as a completedetergent composition the alkali metal pyrophosphate will be present inthe composition at from about 5 to about 60%, preferably about 8 toabout 40%, and most preferably from about 12% to about 27% by weight ofthe composition.

The amount of the alkaline earth metal pyrophosphate in the detergentproduct is from about 1 to about 50%, preferably from about 2 to about30%, and most preferably from about 3% to about 20% by weight of thecomposition. The preferred ratios of the alkali metal pyrophosphate tothe alkaline earth metal pyrophosphate are as previously given for thedetergent additive.

The organic detergent component of the present invention as more fullydescribed below is present at from about 2 to about 40%, preferably fromabout 5 to about 30%, and most preferably from about 10 to about 25% byweight of the total detergent composition.

The supplemental alkaline material discussed above were used inconjunction with the detergent additive aspect of the present inventionmay also be used with the detergent composition of the presentinvention. Suitable organic detergent components which may be usedherein include, for example, the following:

DETERGENT COMPONENT

Preferably the detergent component of the present invention is awater-soluble salt of: an ethoxylated sulfated alcohol with an averagedegree of ethoxylation of about 1 to 4 and an alkyl chain length ofabout 14 to 16; tallow ethoxy sulfate; tallow alcohol sulfates; an alkylbenzene sulfonate with an average alkyl chain length between 11 and 12,preferably 11.2 carbon atoms; a C₆ -C₂₀ α-sulfocarboxylic acid or esterthereof having 1 to 14 carbon atoms in the alcohol radical; a C₈ -C₂₄paraffin sulfonate; a C₁₀ -C₂₄ α-olefin sulfonate or mixtures thereof;or other anionic sulfur-containing surfactant. Such preferred detergentsare discussed below.

An especially preferred alkyl ether sulfate detergent component of thepresent invention is a mixture of alkyl ether sulfates, said mixturehaving an average (arithmetic mean) carbon chain length within the rangeof about 12 to 16 carbon atoms, preferably from about 14 to 15 carbonatoms, and an average (arithmetic mean) degree of ethoxylation of fromabout 1 to 4 moles of ethylene oxide, preferably from about 2 to 3 molesof ethylene oxide.

Specifically, such preferred mixtures comprise from about 0 to 10% byweight of mixture of C₁₂₋₁₃ compounds, from about 50 to 100% by weightof mixture of C₁₄₋₁₅ compounds, and from about 0 to 45% by weight ofmixture of C₁₆₋₁₇ compounds, and from about 0 to 10% by weight of amixture of C₁₈₋₁₉ compounds. Further, such preferred alkyl ether sulfatemixtures comprise from about 0 to 30% by weight of mixture of compoundshaving a degree of ethoxylation of 0, from about 45 to 95% by weight ofmixture of compounds having a degree of ethoxylation from 1 to 4, fromabout 5 to 25% by weight of mixture of compounds having a degree ofethoxylation from 5 to 8, and from about 0 to 15% by weight of mixtureof compounds having a degree of ethoxylation greater than 8. Thesulfated condensation products of ethoxylated alcohols of 8 to 24 alkylcarbons and with from 1 to 30, preferably 1 to 4 moles of ethylene oxidemay be used in place of the preferred alkyl ether sulfates discussedabove.

Another class of detergents which may be used in the present inventionincludes the water-soluble salts, particularly the alkali metal,ammonium, and alkylolammonium salts of organic sulfuric reactionproducts having in their molecular structure an alkyl group containingfrom about 8 to about 22 carbon atoms and a sulfuric acid ester group.Examples of this group of synthetic detergents are the sodium andpotassium alkyl sulfates, especially those obtained by sulfating thehigher alcohols (C₈ -C₁₈ carbon atoms) produced by reducing theglycerides of tallow or coconut oil.

Preferred water-soluble organic detergent compounds herin include alkylbenzene sulfonates (preferably linear although "hard" ABS may be used)containing from about 9 to 15 carbon atoms in the alkyl group. Examplesof the above are sodium and potassium alkyl benzene sulfonates in whichthe alkyl group contains from about 11 to about 12 carbon atoms, instraight chain or branched chain configuration, e.g. those of the typedescribed in U.S. Pat. Nos. 2,220,099 and 2,477,383. Especially valuableare straight chain alkyl benzene sulfonates in which the average of thealkyl groups is about 11.2 carbon atoms, abbreviated as C₁₁.2 LAS.

Another useful detergent compound herein includes the water-solublesalts of esters of α-sulfonated fatty acids containing from about 6 to20 carbon atoms in the fatty acid group and their esters from about 1 to14 carbon atoms in the alcohol radical.

Preferred "olefin sulfonate" detergent mixtures utilizable yereincomprise olefin sulfonates containing from about 10 to about 24 carbonatoms. Such materials can be produced by sulfonation of α-olefins bymeans of uncomplexed sulfur trioxide followed by neutralization underconditions such that any sultones present are hydrolyzed to thecorresponding hydroxy-alkane sulfonates. The α-olefin starting materialspreferably have from 14 to 16 carbon atoms. Said preferred α-olefinsulfonates are described in U.S. Pat. No. 3,332,880, incorporated hereinby reference.

The paraffin sulfonates embraced in the present invention areessentially linear and contain from 8 to 24 carbon atoms, preferably 12to 20 and more preferably 14 to 18 carbon atoms in the alkyl radical.

Other anionic detergent compounds herein include the sodium alkylglyceryl ether sulfates, especially those ethers of higher alcoholsderived from tallow and coconut oil; sodium coconut oil fatty acidmonoglyceride sulfonates and sulfates; and sodium or potassium salts ofalkyl phenol ethylene oxide ether sulfate containing about 1 to about 10units of ethylene oxide per molecule and wherein the alkyl groupscontain about 8 to about 12 carbon atoms.

Water-soluble salts of the higher fatty acids, i.e. "soaps," are usefulas the detergent component of the composition herein. This class ofdetergents includes ordinary alkali metal soaps such as the sodium,potassium, ammonium and alkylolammonium salts of higher fatty acidscontaining from about 8 to about 24 carbon atoms and preferably fromabout 10 to about 20 carbon atoms. Soaps can be made by directsaponification of fats and oils or by the neutralization of free fattyacids. Particularly useful are the sodium and potassium salts of themixtures of fatty acids derived from coconut oil and tallow, i.e. sodiumor potassium tallow and coconut soap.

Water-soluble nonionic synthetic detergents are also useful as thedetergent component of the instant composition. Such nonionic detergentmaterials can be broadly defined as compounds produced by thecondensation of alkylene oxide groups (hydrophilic in nature) with anorganic hydrophobic compound, which may be aliphatic or alkyl aromaticin nature. The length of the polyoxyalkylene group which is condensedwith any particular hydrophobic group can be readily adjusted to yield awater-soluble compound having the desired degree of balance betweenhydrophilic and hydrophobic elements.

For example, a well-known class of nonionic synthetic detergents is madeavailable on the market under the trade name "Pluronic" sold byWyandotte Chemicals. These compounds are formed by condensing ethyleneoxide with a hydrophobic base formed by the condensation of propyleneoxide with propylene glycol. Other suitable nonionic syntheticdetergents include the polyethylene oxide condensates of alkyl phenols,e.g. the condensation products of alkyl phenols having an alkyl groupcontaining from about 6 to 12 carbon atoms in either a straight chain orbranched chain configuration, with ethylene oxide, the said ethyleneoxide being present in amounts equal to 5 to 25 moles of ethylene oxideper mole of alkyl phenol.

The water-soluble condensation products of aliphatic alcohols havingfrom 8 to 22 carbon atoms, in either straight chain or branchedconfiguration, with ethylene oxide, e.g. a coconut alcohol-ethyleneoxide condensate having from 5 to 30 moles of ethylene oxide per mole ofcoconut alcohol, the coconut alcohol fraction having from 10 to 14carbon atoms, are also useful nonionic detergents herein.

Semi-polar nonionic detergents include watersoluble amine oxidescontaining one alkyl moiety of from about 10 to 28 carbon atoms and 2moieties selected from the group consisting of alkyl groups andhydroxyalkyl groups containing from 1 to about 3 carbon atoms;water-soluble phosphine oxide detergents containing one alkyl moiety ofabout 10 to 28 carbon atoms and 2 moieties selected from the groupconsisting of alkyl groups and hydroxyalkyl groups containing from about1 to 3 carbon atoms; and water-soluble sulfoxide detergents containingone alkyl moiety of from about 10 to 28 carbon atoms and a moietyselected from the group consisting of alkyl and hydroxyalkyl moieties offrom 1 to 3 carbon atoms.

Ampholytic detergents include derivatives of aliphatic or aliphaticderivatives of heterocyclic secondary and tertiary amines in which thealiphatic moiety can be straight chain or branched and wherein one ofthe aliphatic substituents contains from about 8 to 18 carbon atoms andat least one aliphatic substituent contains an anionicwater-solubilizing group.

Zwitterionic detergents include derivatives of aliphatic quaternaryammonium, phosphonium and sulfonium compounds in which the aliphaticmoieties can be straight chain or branched, and wherein one of thealiphatic substituents contains from about 8 to 18 carbon atoms and onecontains an anionic water-solubilizing group.

Other useful detergents include water-soluble salts of2-acyloxy-alkane-1-sulfonic acids containing from about 2 to 9 carbonatoms in the acyl group of from about 9 to about 23 carbon atoms in thealkane moiety; β-alkyloxy alkane sulfonates containing from about 1 to 3carbon atoms in the alkyl group and from about 8 to 20 carbon atoms inthe alkane moiety; alkyl dimethyl amine oxides wherein the alkyl groupcontains from about 11 to 16 carbon atoms;alkyldimethyl-ammoniopropane-sulfonates andalkyl-dimethyl-ammonio-hydroxypropane-sulfonates wherein the alkyl groupin both types contains from about 14 to 18 carbon atoms; soaps ashereinabove defined; the condensation product of tallow fatty alcoholwith about 11 moles of ethylene oxide; the condensation product of a C₁₃(avg.) secondary alcohol with 9 moles of ethylene oxide; and alkylglyceral ether sulfates with from 10 to 18 carbon atoms in the alkylradical.

A typical listing of the classes and species of detergent compoundsuseful herein appear in U.S. Pat. No. 3,852,211, to Ohren issued Dec. 3,1974, incorporated herein by reference. The foregoing list of detergentcompounds and mixtures which can be used in the instant compositions isrepresentative of such materials, but is not intended to be limiting.

ADDITIONAL COMPONENTS

It is to be understood that the compositions of the present inventionmay be supplemented by all manner of detergent components. Soilsuspending agents may be included at about 0.5% to 10% by weight such aswater-soluble salts of carboxymethylcellulose,carboxyhydroxymethylcellulose, copolymers of maleic anhydride and vinylethers, and polyethylene glycols having a molecular weight of about 400to 10,000 are common components of the detergent compositions of thepresent invention. Dyes, pigments, optical brighteners, and perfumes canbe added in varying amounts as desired.

Other materials such as fluorescers, antiseptics, germicides, enzymes inminor amounts of anti-caking agents such as sodium sulfosuccinate, andsodium benzoate may also be added.

Additional amounts of water-soluble detergency builders may be added tothe detergent compositions of the present invention. Such inorganicdetergency builder salts include alkali metal carbonates, borates, andbicarbonates. Specific examples of such salts are the sodium andpotassium borates, perborates, bicarbonates, and carbonates. The alkalimetal carbonates are used as co-builders in the same amounts as they arefor a supplemental source of alkalinity as discussed previously.

Examples of suitable organic detergency builder salts are: (1)water-soluble aminopolycarboxylates, e.g. sodium and potassiumethylenediaminetetraacetates, nitrilotriacetates andN-(2-hydroxyethyl)-nitrilodiacetates; (2) water-soluble salts of phyticacid, e.g. sodium and potassium phytates -- see U.S. Pat. No. 2,739,942;(3) water-soluble polyphosphonates, including specifically, sodium,potassium and lithium salts of ethane-1-hydroxy-1,1diphosphonic acid,sodium, potassium and lithium salts of methylene diphosphonic acid,sodium, potassium and lithium salts of ethylene diphosphonic acid, andsodium, potassium and lithium salts of ethane-1,1,2-triphosphonic acid.Other examples include the alkali metal salts ofethane-2-carboxy-1,1-diphosphonic acid, hydroxymethanediphosphonic acid,carbonyldiphosphonic acid, ethane-1-hydroxy-1,1,2triphosphonic acid,ethane-2-hydroxy-1,1,2-triphosphonic acid,propane-1,1,3,3-tetraphosphonic acid, propane-1,1,2,3-tetraphosphonicacid, and propane-1,2,2,3-tetraphosphonic acid; and (4) water-solublesalts of polycarboxylate polymers and copolymers as described in U.S.Pat. No. 3,308,067.

A useful detergent builder which may be employed in the presentinvention comprises a water-soluble salt of a polymeric aliphaticpolycarboxylic acid having the following structural relationships as tothe position of the carboxylate groups and possessing the followingprescribed physical characteristics: (a) a minimum molecular weight ofabout 350 calculated as to the acid form; (b) an equivalent weight ofabout 50 to about 80 calculated as to acid form; (c) at least 45 molepercent of the monomeric species having at least two carboxyl radicalsseparated from each other by not more than two carbon atoms; (d) thesite of attachment of the polymer chain of any carboxyl-containingradical being separated by not more than three carbon atoms along thepolymer chain from the site of attachment of the nextcarboxyl-containing radical. Specific examples of the above-describedbuilders include polymers of itaconic acid, aconitic acid, maleic acid,mesaconic acid, fumaric acid, methylene malonic acid and citraconic acidand copolymers with themselves.

In addition, other builders which can be used satisfactorily includewater-soluble salts of mellitic acid, citric acid, pyromellitic acid,benzene pentacarboxylic acid, oxydiacetic acid, carboxymethyloxysuccinicacid, and oxydisuccinic acid.

The detergent compositions of this invention preferably contain thewater-soluble detergent in a ratio to the total builder present in aweight ratio of from about 10:1 to about 1:10, preferably from about 2:1to about 1:5. The amount of additional builder in either the additive ordetergent compositions of the present invention is from about 2% toabout 30%, preferably from about 5 % to about 20 %.

Certain zeolites or aluminosilicates enhance the function of thealkaline metal pyrophosphate and add building capacity in that thealuminosilicates sequester calcium hardness. One such aluminosilicatewhich is useful in the compositions of the invention is an amorphouswaterinsoluble hydrated compound of the formula Na_(x) (_(x)AlO₂.ySiO₂), wherein x is an integer of from 1 to 1.2 and y is 1, saidamorphous material being further characterized by a Mg⁺ ⁺ exchangecapacity of from about 50 mg eq. CaCO₃ /g to about 150 mg eq. CaCO₃ /g.This ion exchange builder is more fully described in Ireland publishedpatent application 1505/74 to B. H. Gedge et al filed July 16, 1974,herein incorporated by reference.

A second water-insoluble synthetic aluminosilicate ion exchange materialuseful herein has the formula Na_(z) [(AlO₂)_(z).(SiO₂)_(y) ]xH₂ O,wherein z and y are integers of at least 6; the molar ratio of z to y isin the range from 1.0 to about 0.5, and x is an integer from about 15 toabout 264; said aluminosilicate ion exchange material having a particlesize diameter from about 0.1 micron to about 100 microns; a calcium ionexchange capacity of at least about 200 mg eq./g; and a calcium ionexchange rate of at least about 2 grains/gallon/minute/gram. Thesesynthetic aluminosilicates are discussed in Belgium Pat. No. 814,874herein incorporated by reference.

The compositions of the present invention as either a detergent additiveor a complete detergent product may be formulated into liquidcompositions. The solvent or medium for the liquid composition may be amaterial such as water or a mono- or polyhydric alcohol of from 1 to 8carbon atoms. The medium may comprise from about 10 % to about 90 %,preferably from about 20 % to about 70 % by weight of the totalcomposition. Preferred liquid mediums are water, ethanol, glycerine, andethylene glycol.

COMPOSITION PREPARATION

The detergent additive of the complete detergent product of the presentinvention may be formulated as a liquid paste or solid composition.

When prepared as a liquid the compositions of the present invention areslurried in the solvent medium and packaged. To prevent the settling outof the less soluble materials, electrolytes such as potassium chlorideor other known suspending agents, may be added to the composition inminor amounts. To prepare the paste form of the present invention an theamount of solvent medium is employed is such that the product becomesextremely viscous.

When the additive or complete detergent product of the present inventionis formulated as a solid, the product may be in the form of homogenousgranule or may be present as separately admixed granules. To prepare theadditive or complete detergent composition in the form of homogenousgranules the product is slurried and then formed into granules by spraydrying, drum drying, freeze drying, or agglomeration. Of the methods ofhomogenous granule formation, spray drying is preferred as the granuleshave greater uniformity of size.

Spray drying of the additive or detergent compositions of the presentinvention is best carried out as set forth in U.S. Pat. Nos. 3,629,951and 3,629,955 to Davis et al, issued Dec. 28, 1971.

Where the detergent or the additive composition is formed by admixture,it is preferable to include a small amount of binding agent to preventsegregation of the ultrafine alkaline earth metal pyrophosphatecrystallization seed from the remaining much larger granules of thecomposition. Suitable binding agents include for instance polyethyleneglycol which may be sprayed onto the detergent or additive compositionto prevent such segregation. Preferably the polyethylene glycol has amolecular weight ranging from about 400 to about 10,000.

The detergent additive or complete detergent composition of the presentinvention will most effectively be used at concentrations where theunique builder system of the present invention is present in amountsufficient to control substantially all of the calcium hardness present.Generally the compositions of the present invention will be used at fromabout 0.05% to about 0.5% by weight of the wash solution.

The additive aspect of the present invention may be used as a soaksolution prior to washing the clothes for a period of from a few minutesto several hours. The additive composition may also be used to augmentthe consumer's regular detergent product. The detergent compositions ofthe present invention are otherwise used in the same manner asconventional detergent products presently being marketed.

Following are Examples of the present invention:

EXAMPLE I

Detergent additives are prepared in accordance with the invention havingthe following compositions:

    A                                                                             97.5%        sodium pyrophosphate                                             2.4%         dicalcium pyrophosphate (mean                                                  particle diameter 0.01μ)                                     0.1%         minors                                                           B                                                                             11.0%        sodium pyrophosphate                                             88.8%        dicalcium pyrophosphate (mean                                                  particle diameter 25μ)                                       0.2%         minors                                                       

Products A and B are tested at a concentration of 0.2% by weight forhardness control in 11 grain water by presoaking clay soiled dacronpolyester swatches for 1 hour in 100°F. water followed by washing thefabrics with a detergent product (at 0.12% by weight) at the sametemperature. The detergent product had the following composition:

    20%          sodium alkyl (12 carbons benzene                                               sulfonate)                                                      20%          sodium carbonate                                                 40%          sodium sulfate                                                   12%          moisture                                                          8%          minors                                                       

Products A and B as used above show increased detergency as measured bya Hunter Whiteness meter over control swatches which are treated withthe detergent alone.

EXAMPLE II

Detergent products A, B and C are prepared by spray drying.

    ______________________________________                                                         A      B        C                                            ______________________________________                                        Sodium alkyl (12 carbons)                                                      benzene sulfonate  5%      22%      --                                       Sodium coconut triethoxy                                                       sulfate           --        5%      15%                                      Sodium pyrophosphate                                                                             30%      34%      60%                                      Sodium sulfate     50%      14%      --                                       Dicalcium pyrophosphate                                                        (mean particle diam-                                                                            10%      15%      20%                                       eter 3μ)                                                                  Minors              5%      10%       5%                                      ______________________________________                                    

Compositions A, B, C are tested for cleaning and hardness controlcompared to the detergent described in Example I. A, B, and C performbetter under the conditions of Example I than does the detergent productdisclosed therein.

A, B, C may be modified to form liquid compositions by adding the driedproduct to water so that the water makes up 70% of the total product.

What is claimed is:
 1. A detergent additive comprising:a. an alkalimetal pyrophosphate; and b. an alkaline earth metal pyrophosphatehavinga mean particle diameter of less than 25 microns; in a weightratio of the alkali metal pyrophosphate to the alkaline earth metalpyrophosphate of from about 60:1 to about 1:8.
 2. The composition ofclaim 1 additionally comprising a supplemental alkaline material at fromabout 1% to about 30% by weight selected from the group consisting ofalkali metal carbonates, and alkali metal and alkaline earth metalhydroxides and mixtures thereof.
 3. The composition of claim 1 whereinthe alkaline earth metal pyrophosphate is calcium or magnesiumpyrophosphate.
 4. The composition of claim 3 wherein the mean particlediameter of the alkaline earth metal pyrophosphate is from about 0.01 toabout 1 micron.
 5. The composition of claim 4 wherein the weight ratioof the alkali metal pyrophosphate to the alkaline earth metalpyrophosphate is from about 20:1 to about 1:1.
 6. The composition ofclaim 5 wherein the alkaline earth metal pyrophosphate is the calciumsalt.
 7. The composition of claim 6 wherein the alkali metalpyrophosphate is the sodium salt.
 8. The composition of claim 2 whereinthe supplemental alkaline material is sodium carbonate.
 9. A detergentcomposition comprising:a. from about 5% to about 60% by weight of analkali metal pyrophosphate; b. from about 1% to about 50% by weight ofan alkaline earth metal pyrophosphate having a mean particle diameter ofless than 25 microns and c. from about 2% to about 40% by weight of anorganic detergent surfactant component.
 10. A detergent composition inaccordance with claim 9 wherein the organic detergent is selected fromthe group consisting of anionic and nonionic detergents and mixturesthereof.
 11. The detergent composition of claim 10 wherein the meanparticle diameter of the alkaline earth metal pyrophosphate is fromabout 0.01 to about 1 micron.
 12. The detergent composition of claim 11wherein the weight ratio of the alkali metal pyrophosphate to thealkaline earth metal pyrophosphate is from about 20:1 to about 1:1. 13.The detergent composition of claim 12 wherein the alkali metalpyrophosphate and the alkaline earth metal pyrophosphate are sodiumpyrophosphate and calcium pyrophosphate.
 14. The detergent compositionof claim 13 wherein the sodium pyrophosphate is present at from about 8%to about 40%, the calcium pyrophosphate is present at from about 2% toabout 30%, and the detergent is present at from about 5% to about 30% byweight.
 15. The detergent composition of claim 14 wherein the detergentcomponent is a nonionic selected from the group consisting ofalkoxylated alcohols and alkoxylated alkyl phenols having from 8 to 20carbon atoms in the alkyl radical and from 1 to 30 alkoxy units peralkyl radical and mixtures thereof.
 16. The detergent composition ofclaim 15 wherein the nonionic is an ethoxylated alcohol wherein thealcohol residue with from 10 to 16 carbon atoms and the degree ofethoxylation is from 1 to 10 moles of ethylene oxide per mole of alcoholresidue.
 17. The detergent composition of claim 14 wherein the detergentcomponent is anionic.
 18. The composition of claim 17 wherein theanionic detergent is selected from the group consisting of the alkalimetal and ammonium salts of alkyl ether sulfates, alkyl benzenesulfonates, alkyl sulfates, and alpha-sulfocarboxylic acids.
 19. Thedetergent composition of claim 9 additionally comprising a supplementalalkaline material at from about 1% to about 30% by weight selected fromthe group consisting of alkali metal carbonates, alkali metal, andalkaline earth metal hydroxides and mixtures thereof.